JP3731620B2 - Method for forming hollow helical gear and mold used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to heading molding method and the mold of the hollow helical gear, to a heading molding method and the mold can be produced a type of gear which is present teeth to both ends of the gear at a low cost.
[0002]
[Prior art]
Conventionally, the following three methods have been mainly employed for manufacturing pinion gears. (1) First, the first manufacturing method cuts a normal round steel material into a predetermined length, and goes through a series of steps such as blanking, gear processing with a bob machine, burring, shaving, heat treatment, end surface polishing, and inner diameter polishing. Method. (2) Next, the second manufacturing method is a cold forging knockout type, in which an annealed round steel material is cut into a predetermined length, subjected to blanking, and then bonded, geared, and cut. In this method, gears are obtained by performing processing, burring, shaving, heat treatment, end face polishing, and inner diameter polishing. (3) Further, the third manufacturing method is a cold forging and knockout type, which will be described in detail with reference to FIGS. 7 to 9, but the coil steel material that has been annealed and bonded is cut to a predetermined length, Using a mold 2 having a die 1 shown in FIG. 7, a coil steel material of a predetermined length loaded inside is pressed by a punch 3 to form a gear by forging the coil material onto the die 1. The gear 4 molded in the molding die 2 is a manufacturing method in which a striking force is applied to the knockout sleeve 5 from the opposite side via the knockout pin 6 as shown in FIGS.
[0003]
[Problems to be solved by the invention]
In the conventional cold forging and knockout method shown in (3) above, there is a problem that the die is narrowed at the back side of the die, and the corners are sagging, and when it is forced to return to the inlet direction. In addition to the difficulty of reducing gear accuracy, there is a heel for stretching the mold at the base of the mold. There is a waste of processing process. Therefore, the present invention aims to provide a forging method and a mold used therefor, in which there is no waste of material, gears can be manufactured with high efficiency, and the accuracy of the manufactured gears is high.
[0004]
[Means for Solving the Problems]
As a result of studying the above problems, the coil steel material or bar steel material was cut into a predetermined length to obtain a workpiece, and the workpiece was formed into a gear by forging using a self-knockout mold by part former molding or press molding. Parts former molding here refers to various processes for making gears, that is, dies for performing multiple processes such as imposition, drilling, gear machining, etc., are arranged in series, and the workpieces are arranged in series. This means continuous molding that is processed while moving the mold. Press molding is a molding method in which the gear machining portion is the same as that performed with a self-knockout mold, but the other machining steps are performed separately. Both the part former molding and the press molding can be performed in any of the cold and hot cases.
The method for manufacturing a hollow helical gear according to the present invention is to cut a coil steel material or a bar steel material into a predetermined length to obtain a workpiece, and by using a die of a self-knockout method by part former molding or press molding, imposition and drilling on the workpiece, When a plurality of gear processing steps are arranged in series, and the workpiece is processed while moving the mold, the workpiece is processed into a helical gear by forging.
(a) The process of making a workpiece cut from coil steel with a predetermined length
(b) one imposition of the work (that removing the corner) to step
(c) Inverting the workpiece and imposing on the opposite side
(d) Upsetting process to compress and crush in the axial direction to increase and shape the workpiece
(e) (f) Process for forming a through hole by making a hole on one side of a workpiece
(g) Forming helical gears using a self-knockout mold
It is characterized by comprising.
[0005]
The mold has a structure having one of the workpiece insertion port and punch insertion hole on one side, a gear forming die in the middle, and a gear take-out port on the other side. That is, it has a work insertion port and punch insertion hole for inserting a workpiece by one or a plurality of punches on one side, a gear forming die in the middle, and a gear take-out port on the other side,
The punch is a hollow helical gear forging mold that is stepped so that a plurality of workpieces can be mounted.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a cold forging step which is an embodiment of the gear forging forming method of the present invention. (a) is a workpiece 11 cut from the coil steel material 10 by a predetermined length. In (b), one end of the work 11 is impositioned (the corner is removed). In (c), the work is reversed and impositioned on the opposite side. Next, there is a process called (d) upsetting, compressing in the axial direction and crushing. With this, the workpiece with increased strength is drilled through one side with (e) and (f). The details of the work 11 will be described later with reference to FIGS. 2 to 5, and the gear 12 as shown in FIG. 5G is formed using a self-knockout mold. As a matter of course, the steps up to here can be carried out in both the part former molding and the press molding, and in both the cold and hot cases.
[0007]
The mold will be described in detail with reference to the cross-sectional views of FIGS. 2 to 5. The mold has a punch insertion hole 13 serving as an insertion port for the workpiece on the left side of the drawing, a gear forming die 14 in the middle, A gear outlet 15 is provided. The workpiece 11 inserted into the punch insertion hole 13 is forcibly fed toward the gear forming die 14 by the punch 16, and in this example, cold work is performed. The punch 16 has a base side in the punch case 17 and forcibly hits or presses the punch plate 18 at the end. A gear forming die 14 having a different structure depending on the type of gear to be manufactured is appropriately held in the die holder 19. There is a die spacer 20 on the right side of the gear forming die 14, and a gear take-out port 15 is provided therebelow.
[0008]
When one of the workpieces 11 is forcibly fed through the gear forming die 14 to a predetermined position by the punch 16 as shown in FIG. 2, the punch 16 is pulled out and the next workpiece 11 is inserted as shown in FIG. When the operation is repeated as shown in FIG. 4, as shown in FIG. In the system in which the gear 12 is manufactured in this tokoroten type, as shown in FIG. 6, it is possible to manufacture the work 22 having a throttle portion in the middle. Of course, it is also possible to manufacture a single gear. In the above-described embodiment, an example of manufacturing a hollow gear is shown, but it is also possible to manufacture a solid gear.
[0009]
【The invention's effect】
Since the present invention is as described above, an operation of removing the sag portion and the flange portion of the manufactured gear is not required, so that the material yield can be improved and the thickness removal time can be shortened. In addition, the precision of the manufactured gear is good, and in the case of forging, the strength can be improved by the orientation of the metal flow in the same direction without cutting the orientation metal flow as in the case of cutting.
[0010]
These small helical gears are used in large quantities as sun gears and planetary gears in automotive automatic transmissions, so their increased strength and reduced manufacturing costs greatly contributed to durability and cost reduction. .
[Brief description of the drawings]
FIGS. 1A to 1G are cold forging process diagrams showing an embodiment of a gear forging forming method according to the present invention.
FIG. 2 is a cross-sectional view during manufacturing of a gear using the gear forging molding die of the present invention.
FIG. 3 is a cross-sectional view during manufacturing of a gear by increasing the number of workpieces.
FIG. 4 is a sectional view of the same.
FIG. 5 is a cross-sectional view when the gear is manufactured.
FIG. 6 is an enlarged view of a gear forming die portion.
FIG. 7 is a cross-sectional view of a conventional cold forging and knockout type gear production.
FIG. 8 is a cross-sectional view of the same mold when the gear is taken out.
FIG. 9 is an enlarged view of a die portion of the mold.
[Explanation of symbols]
10 Coil steel
11 Work
12 gear
13 Punch insertion hole
14 Gear forming die
15 Gear outlet
16 punches
17 Punch case
18 Punch plate
19 Die holder
20 Die spacer
22 Workpiece

Claims (2)

Upon coil steel or by cutting the bar steel in a predetermined length to the work, by using a mold of the self-knockout fashion by part former molding or press molding, the helical gear by heading the work,
(a) The process of making a workpiece cut from coil steel with a predetermined length
(b) one imposition of the work (that removing the corner) to step
(c) Inverting the workpiece and imposing on the opposite side
(d) Upsetting process to compress and crush in the axial direction to increase and shape the workpiece
(e) (f) Process for forming a through hole by making a hole on one side of a workpiece
(g) Forming helical gears using a self-knockout mold
A method for forming a hollow helical gear by forging. Mold self knockout method according to claim 1 has a workpiece insertion port and the punch insertion holes for inserting the plurality punch the workpiece in one, intermediate has a gear forming die, the other to the gear outlet a Ri Na, the said punch hollow helical gear forging mold Ru der stepped can be mounted multiple workpieces.

Images